Drug & supplement interaction

Oolong Tea + Ethinyl Estradiol, Norethindrone

Ethinyl Estradiol, Norethindrone brand names: Femhrt, Loestrin 21, Ovcon 35 21, Ovcon 50 28, Necon 0.5 35 21, and others.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Ethinyl Estradiol, Norethindrone falls into 3 drug categories that Oolong Tea can interact with; the most serious is rated moderate. Theoretically, concomitant use might increase the levels and adverse effects of the caffeine in oolong tea.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Oolong Tea and Ethinyl Estradiol, Norethindrone

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Oolong Tea interacts with whole categories of medication. Ethinyl Estradiol, Norethindrone falls into 3 of those categories, so it can interact with Oolong Tea in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 1A2 (CYP1A2) INHIBITORS

1 of 3

Why this applies to Ethinyl Estradiol, Norethindrone

Ethinyl Estradiol, Norethindrone falls under CYTOCHROME P450 1A2 (CYP1A2) INHIBITORS — the group Oolong Tea interacts with.

Theoretically, concomitant use might increase the levels and adverse effects of the caffeine in oolong tea.
Oolong tea contains caffeine. Caffeine is metabolized by cytochrome P450 1A2 (CYP1A2),. Theoretically, drugs that inhibit CYP1A2 may decrease the clearance rate of caffeine from oolong tea and increase caffeine levels.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing to keep in mind with your birth control pill (the ethinyl estradiol and norethindrone combo): the estrogen part can gently slow down the same liver enzyme, called CYP1A2, that your body uses to clear caffeine. Since oolong tea has caffeine, drinking it while on the pill could let that caffeine hang around a bit longer than usual.

In practice, that might mean you feel caffeine's effects more strongly: a little jittery, a racing heart, trouble sleeping, or a touch of nausea. This is theoretical and based on pharmacology, not strong studies, and a cup or two of tea usually isn't a big deal. If you're caffeine-sensitive or notice these effects, just ease up and chat with your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Weisburger JH. Tea and health: the underlying mechanisms. Proc Soc Exp Biol Med 1999;220:271-5. PubMed
  2. Hagg S, Spigset O, Mjorndal T, Dahlqvist R. Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. Br J Clin Pharmacol 2000;49:59-63. PubMed
  3. Carrillo JA, Benitez J. Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clin Pharmacokinet 2000;39:127-53. PubMed
  4. Kot, M. and Daniel, W. A. Effect of diethyldithiocarbamate (DDC) and ticlopidine on CYP1A2 activity and caffeine metabolism: an in vitro comparative study with human cDNA-expressed CYP1A2 and liver microsomes. Pharmacol Rep. 2009;61(6):1216-1220. PubMed
  5. Wojcikowski, J. and Daniel, W. A. Perazine at therapeutic drug concentrations inhibits human cytochrome P450 isoenzyme 1A2 (CYP1A2) and caffeine metabolism--an in vitro study. Pharmacol Rep. 2009;61(5):851-858. PubMed
  6. Wang, X. and Yeung, J. H. Effects of the aqueous extract from Salvia miltiorrhiza Bunge on caffeine pharmacokinetics and liver microsomal CYP1A2 activity in humans and rats. J Pharm Pharmacol 2010;62(8):1077-1083.
  7. Kot M, Daniel WA. Caffeine as a marker substrate for testing cytochrome P450 activity in human and rat. Pharmacol Rep 2008;60:789-97.
  8. Kjaerstad MB, Nielsen F, Nohr-Jensen L, et al. Systemic uptake of miconazole during vaginal suppository use and effect on CYP1A2 and CYP3A4 associated enzyme activities in women. Eur J Clin Pharmacol 2010;66:1189-97. PubMed
  9. Goh BC, Reddy NJ, Dandamudi UB, et al. An evaluation of the drug interaction potential of pazopanib, an oral vascular endothelial growth factor receptor tyrosine kinase inhibitor, using a modified Cooperstown 5+1 cocktail in patients with advanced solid t
  10. Chen Y, Kang Z, Yan J, et al. Liu wei di huang wan, a well-known traditional Chinese medicine induces CYP1A2 while suppressing CYP2A6 and N-acetyltransferase 2 acivities in man. J Ethnopharmacol 2010;132:213-8.
  11. Suzuki S, Murayama Y, Sugiyama E, et al. Estimating pediatric doses of drugs metabolized by cytochrome P450 (CYP) isozymes, based on physiological liver development and serum protein levels. Yakugaku Zasshi 2010;130:613-20. PubMed
  12. Chien CF, Wu YT, Lee WC, et al. Herb-drug interaction of Andrographis paniculata extract and andrographolide on the pharmacokinetics of theophylline in rats. Chem Biol Interact 2010;184:458-65. PubMed
  13. Mills BM, Zaya MJ, Walters RR, et al. Current cytochrome P450 phenotyping methods applied to metabolic drug -drug interaction prediction in dogs. Drug Metab Dispos 2010;38:396-404. PubMed
  14. Turpault S, Brian W, Van Horn R, et al. Pharmacokinetic assessment of a five-probe cocktail for CYPs 1A2, 2C9, 2C19, 2D6, and 3A. Br J Clin Pharmacol 2009;68:928-35. PubMed
  15. Filimonova AA, Ziganshina LE, Ziganshin AU, Chichirov AA. On the possibility of patient phenotyping on the basis of cytochrome p-450 1A2 isoenzyme activity using caffeine as the test substrate. Eksp Klin Farmakol 2009;72:61-5.
  16. Jenkins J, Williams D, Deng Y, et al. Eltrombopag, an oral thrombopoietin receptor agonist, has no impact on the pharmacokinetic profile of probe drugs for cytochrome P450 isoenzymes CYP3A4, CYP1A2, CYP2C9 and CYP2C19 in healthy men: a cocktail analysis.
  17. Perera, V., Gross, A. S., and McLachlan, A. J. Caffeine and paraxanthine HPLC assay for CYP1A2 phenotype assessment using saliva and plasma. Biomed.Chromatogr. 2010;24(10):1136-1144. PubMed
  18. Izzo, A. A. and Ernst, E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs 2009;69(13):1777-1798. PubMed
Moderate

ESTROGENS

2 of 3

Ethinyl Estradiol, Norethindrone also falls under ESTROGENS.

Theoretically, estrogens might increase the levels and adverse effects of caffeine in oolong tea.
Oolong tea contains caffeine. Estrogen inhibits caffeine metabolism.
Severity Moderate Likelihood Probable Evidence B

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing to know about this combo: it actually works the other way around from what you might expect. The estrogen in your birth control pill (the ethinyl estradiol part) slows down how fast your body clears caffeine. So the caffeine from your oolong tea sticks around longer than it normally would. Your pill isn't the one being affected here, the caffeine is.

What that can feel like in real life: a little more jittery, a racing or pounding heart, trouble sleeping, or feeling wired after just a cup or two. It's usually mild, and a moderate amount of tea is fine for most people. If you notice these things, easing up on the caffeine often does the trick. Any concerns, just check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40. PubMed
Minor

CONTRACEPTIVE DRUGS

3 of 3

Ethinyl Estradiol, Norethindrone also falls under CONTRACEPTIVE DRUGS.

Theoretically, concomitant use might increase the effects and adverse effects of caffeine in oolong tea.
Oolong tea contains caffeine. Oral contraceptives decrease the rate of caffeine clearance by 40% to 65%.
Severity Minor Likelihood Possible Evidence B

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing to keep in mind with your birth control pill (the ethinyl estradiol and norethindrone combo) and that cup of oolong tea: the interaction actually works on the caffeine, not on the pill itself. The hormones in your contraceptive slow down how fast your liver clears caffeine, sometimes by 40% to 65%. So the caffeine sticks around in your body longer than it normally would.

In plain terms, the same amount of tea may hit you a little harder. You might notice more jitteriness, a faster heartbeat, trouble sleeping, or feeling wired. This is considered a minor interaction, and a cup or two is usually fine for most people. If you're caffeine-sensitive or it bugs you, just cut back or switch to decaf, and check with your pharmacist if you have questions.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40. PubMed
  2. Abernethy DR, Todd EL. Impairment of caffeine clearance by chronic use of low-dose oestrogen-containing oral contraceptives. Eur J Clin Pharmacol 1985;28:425-8. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Oolong Tea Also Interacts With Other Medications

Oolong Tea has 8 major, 517 moderate, 126 minor known drug interactions in our database — the Ethinyl Estradiol, Norethindrone one above is among them. If you take anything else, check it against the full list below.

Major 8 Moderate 517 Minor 126 No known interaction 2,179 (incl. Ethinyl Estradiol, Norethindrone)
Taking anything else?

Check Another of Your Medications Against Oolong Tea

Covers the 2,830 medications we’ve checked against Oolong Tea. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Ethinyl Estradiol, Norethindrone

This page covers Oolong Tea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ethinyl Estradiol, Norethindrone page lists 240 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 196 moderate · 38 minor.

From our pharmacist’s overview on the Ethinyl Estradiol, Norethindrone page

“If you take a birth control pill or hormone therapy containing ethinyl estradiol and norethindrone (Loestrin, Femhrt, and others), a few supplements can genuinely undermine it, so read this page with care. Six of the 240 ingredients on file are rated major, and those six come first.”

Reviewed by 2 · Jul 18, 2026

Open the Ethinyl Estradiol, Norethindrone interaction page

One more smart check

Taking Oolong Tea as Part of a Dietary Supplement Product? Check It for Interactions

We hold 75 real supplement products containing Oolong Tea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Oolong Tea. Your product may carry other ingredients that interact with Ethinyl Estradiol, Norethindrone too, on top of Oolong Tea — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Oolong Tea and Ethinyl Estradiol, Norethindrone Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Oolong Tea
Steady interest

#1,142 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Ethinyl Estradiol, Norethindrone
Top 25%

#347 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Oolong Tea

What is Oolong Tea?

  • Weight management
  • Mental alertness and energy
  • Heart health
  • Blood sugar support
  • Antioxidant support

Oolong tea is a traditional partially oxidized tea made from the same plant as green and black tea, and it provides caffeine and plant antioxidants. As a beverage it is generally considered safe for most healthy adults in moderate amounts, but evidence for specific health benefits like weight loss or blood sugar control is limited. If you have heart, blood pressure, or caffeine-sensitivity concerns, talk with your pharmacist or doctor.

Read the full Oolong Tea monograph & all interactions
Keep checking

Other Drugs & Oolong Tea

Browse every other medication we’ve checked against Oolong Tea — both the ones with a known interaction and the ones without. Select any drug for the full detail.

8Major
517Moderate
126Minor
2,178No known interaction
8 Major 517 Moderate 126 Minor 2,178 No interaction
Major

8 interactions

Moderate

517 interactions

Showing 60 of 517 moderate interactions — see all 517 on the Oolong Tea page.

Minor

126 interactions

Showing 60 of 126 minor interactions — see all 126 on the Oolong Tea page.

No interaction 2,178 drugs checked — show the list

We also checked Oolong Tea against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,178 medications checked with no known interaction — see the full Oolong Tea list.

See the full Oolong Tea interactions page
See every supplement checked against Ethinyl Estradiol, Norethindrone, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Oolong Tea monograph › Uses, safety, and every drug interaction in one place Ethinyl Estradiol, Norethindrone supplement interactions › Every supplement checked against Ethinyl Estradiol, Norethindrone, ranked by severity Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Oolong Tea and Ethinyl Estradiol, Norethindrone Together: Common Questions

Can you take Oolong Tea with Ethinyl Estradiol, Norethindrone?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 3 interactions listed for Oolong Tea and Ethinyl Estradiol, Norethindrone?
Ethinyl Estradiol, Norethindrone belongs to more than one drug category, and Oolong Tea interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Oolong Tea and Ethinyl Estradiol, Norethindrone interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.